1. Field of the Invention
This invention relates to a process for making selected 3-trihalomethyl-5-lower alkoxy-1,2,4-thiadiazole compounds.
2. Description of the Prior Art
3-Trichloromethyl-5-lower alkoxy-1,2,4-thiadiazole compounds are known as effective soil fungicides. See U.S. Pat. Nos. 3,260,588 and 3,260,725, both of which were issued to H. A. Schroeder on July 17, 1966. As noted in these Schroeder patents, 3-trichloromethyl-5-lower alkoxy-1,2,4-thiadiazole compounds have been prepared by first reacting trichloroacetamidine or its hydrochloride with trichloromethane sulfenyl chloride in the presence of alkali to form 3-trichloromethyl-5-chloro-1,2,4-thiadiazole. This 5-chloro compound is then reacted with alkali metal in the excess of lower alcohol. Also see U.S. Pat. Nos. 3,890,338 and 3,890,339, which issued to Wojtowicz et al. and Gavin, respectively, on June 17, 1975.
While this reaction route for making 3-trichloromethyl-5-lower alkoxy-1,2,4-thiadiazole compounds has certain characteristics which make it commercially desirable, the present invention presents a new and simple alternate route for producing these compounds without making the 3-trichloromethyl-5-chloro-1,2,4-thiadiazole intermediate. Ring closure directly produces the desired 5-lower alkoxy compounds.